Tri-axis angle sensor

Patent Granted PROBLEM TO BE SOLVED: To provide a tri-axis angle sensor capable of measuring the small angle variations around three axes of an object to be measured, and being also reduced in size. ; SOLUTION: Parallel incident light 6 is projected from a light source to a uniaxial rectangular grate 1a provided on a surface 1 to be detected. Quadrant photodiodes (PDs) 3a, 3b and 3c are provided in the optical path of diffraction light reflected components 7<SB>0</SB>, 7<SB>1</SB>and 7<SB>2</SB>from the grate 1a.